The numismatic chronicle and journal of the Royal ... - IndianCoins.org

THE ORIGIN OF WEIGHT. 345written works will show. The following are preservedto us : On the Sphere and Cylinder, On the Measurementof the Circle, On Conoids and Spheroids, On Spiral Lines,The Psammites (sand-reckoners), On the Equilibrium ofPlanes and their Centres of Gravity, and On FloatingBodies. The course of his studies is very clear, and thehydrostatical element involved in his work on floatingbodies would naturally bring before him the importantfactor of the weight of water displaced by a givenenclosed body. Upon this displaced weight of water,which obviates the necessity of accurately measuring thesurfaces of an enclosed body, in order to arrive at itscontents, the modern and easy method of estimating thespecific gravity of a substance is based. It was onlythis simple method of determining the weight percapacity that Archimedes discovered. To obtain therequired result before his time, accurate surface measurementswere necessary, and certain shapes, as, for example,the crown, which has been made famous by the popularstory of his discovery, offered insuperable difficulties.Hence, it is natural in every way that, in days so longbefore his time as those of the Middle Egyptian Kingdom,we should find that precious material was measuredbefore it was weighed, and that it was manufactured intodefinite shapes for that purpose, e.g. rings in Egypt.There is, as we have shown, much corroborativeevidence of this measuring and weighing ; there is alsomention of flat plates of gold " which could not beweighed," 23 presumablybecause their worked surfacesdefied measurement. The inscription of Thutiy 24 gives23Annals of Thutmose III. Breasted, ii. 447.24 Inscription of Thutiy. Idem, ii. 377.